1. Field of the Disclosure
This disclosure pertains to data communications, and more specifically to High-bandwidth Digital Content Protection (“HDCP”) link verification when transmitting digital media.
2. Description of the Related Art
High-bandwidth Digital Content Protection (“HDCP”) prevents copying of digital media content when it is transmitted across devices by connections that comply with various protocols such as DisplayPort (“DP”), Digital Visual Interface (“DVI”), and High-Definition Multimedia Interface (“HDMI”). Media content that is HDCP-encrypted can only be played on devices that are authorized by a licensing entity (e.g., Digital Content Protection LLC).
During the authentication process, a sending HDCP device exchanges authentication data with a receiving HDCP device. After the authentication process, the sending HDCP device encrypts data by XOR processing content data with a pseudo random data generated by a HDCP cipher. At the receiving HDCP device, the encrypted data is again XOR processed by the same pseudo random data generated, this time, by another HDCP cipher at the receiving HDCP device.
However, when encrypting and transmitting digital media using HDCP, digital media transmission may experience unexpected transmission noise. Such transmission noise can occur, for example, in the form of ground noise. As a result of unexpected transmission noise, synchronization of an HDCP link between an HDCP transmitter and an HDCP receiver may be disrupted, which may require re-establishing of the HDCP link. For example, when an HDCP receiver detects Error Correction Code (“ECC”) errors exceeding a threshold, an HDCP transmitter may need to re-authenticate the HDCP receiver. Re-authenticating and re-establishing synchronization of an HDCP link consumes time and resources and may disturb users' experience.